At the end of March, 1991, we completed a NIDR-sponsored contract with the specific task of ascertaining the effect of a chemotherapeutic intervention on preventing or delaying the transmission of mutans streptococci (MS) from mothers to their infants. Mothers deemed "high risk, " based upon their past caries experience and high levels of MS in saliva, received comprehensive dental restorative treatments followed by a series of applications of either iodine-NaF or placebo solutions. Mothers' and infants' bacterial profiles prior to and following intervention were monitored until the child's 3rd birthday. Having answered the initial aims of the contract, we have amassed a comprehensive database on 48 mother- infant pairs; detailed bacteriological profiles taken at 3 mo. intervals, including levels of oral MS, lactobacilli, S. sanguis, total streptococci, and total cultivable bacteria in saliva of mothers, and plaque and saliva of infants. To our knowledge, this constitutes the only database of this kind in the world. Frozen stores of mutans streptococci, other bacterial species, and salivary immunoglobulins are also available for analysis. In addition, based on the observations made in this study regarding the potential factors associated with the acquisition of MS by children, we have gathered complementary data from 353 inner city children between the ages 5-12 years and their mothers in a cross-sectional study. The overall goal of the study proposed here is to use these two existing databases, as well as the results of the subsequent yearly examinations to formulate prediction models for acquisition of MS and other bacteria (e.g., S. sanguis) and caries development in children. This will be accomplished using regression analysis techniques, including a technique called generalized equating equation (GEE). Since observations are made on the same person over time in the longitudinal study, GEE can adjust for within- person correlation of independent variables. Possible predictors of MS colonization and/or caries outcome in the child, based on mother's characteristics, include past dental and medical histories of the mother, salivary bacterial profiles, age, race, and diet history, among others. Potential predictors from infant/child data include demographic as well as other risk factors; timing and pattern of tooth eruption, sequence of bacterial colonization, caretaker history, fluoride, antibiotic exposure, and diet. Birth weight and gestational age of each child are available and will be included in some of the analyses. Results of this study will allow identification of predictors for MS colonization and caries in children to focus public health measures at identifying infants deemed "high risk." This in turn will allow specified health dollars to be directed toward preventive measures for those individuals. Basic information will be obtained concerning well as disease, and insight into other infectious diseases affecting infants and young children.